Function parseMaxParts

core/src/components/datetime/utils/parse.ts:158–195

(max: string, todayParts: DatetimeParts)

 * month, day, hour, and minute information.
 */
export const parseMaxParts = (max: string, todayParts: DatetimeParts): DatetimeParts | undefined => {
  const result = parseDate(max);

  /**
   * If min was not a valid date then return undefined.
   */
  if (result === undefined) {
    return;
  }

  const { month, day, year, hour, minute } = result;

  /**
   * When passing in `max` or `min`, developers
   * can pass in any ISO-8601 string. This means
   * that not all of the date/time fields are defined.
   * For example, passing max="2012" is valid even though
   * there is no month, day, hour, or minute data.
   * However, all of this data is required when clamping the date
   * so that the correct initial value can be selected. As a result,
   * we need to fill in any omitted data with the min or max values.
   */

  const yearValue = year ?? todayParts.year;
  const monthValue = month ?? 12;
  return {
    month: monthValue,
    day: day ?? getNumDaysInMonth(monthValue, yearValue),
    /**
     * Passing in "HH:mm" is a valid ISO-8601
     * string, so we just default to the current year
     * in this case.
     */
    year: yearValue,
    hour: hour ?? 23,
    minute: minute ?? 59,
  };
};

/**
 * Takes a min date string and creates a DatetimeParts